#define _CRT_SECURE_NO_WARNINGS

#include<stdio.h>


int main()
{
	int arr[10] = { 0 };
	for (int i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
	}
	double sum = 0;
	for (int i = 0; i < 10; i++)
	{
		sum += arr[i];
	}
	printf("%lf",sum/10);
	return 0;
}